1 Indications top
Soft-tissue integrity is an essential prerequisite for open reduction and plate fixation of metatarsal shaft fractures.
Should there be compromise of the surrounding soft tissues, percutaneous pinning may be a safer option.
2 Principles topenlarge
Proper alignment of the metatarsal heads is a critical goal in restoring the pathomechanics of the forefoot. On the AP view, a normal curved “cascade” (Lelièvre’s parabola) appearance, symmetric with the other foot, is mandatory. See illustration.
This ensures that the normal length of the metatarsal is restored.
It is also critical to restore the metatarsals in their axial or horizontal plane so that in the axial or tread view all the metatarsal heads are on the same level.
Any malalignment particularly flexion will recreate focally high pressure during the stance phase and toe-off and will result in pain and subsequent callus formation.
Note that for the first ray, it is the sesamoids rather than the first metatarsal head, that bear weight, and therefore one must look at the sesamoid level in establishing the alignment in the axial or horizontal plane of the first metatarsal.
3 Approach and reduction topenlarge
One or multiple diaphyseal metatarsal fractures or dislocations can best be approached through appropriately placed dorsal incision(s) (see Dorsal intermetatarsal approach).
Manual traction on the toe, as illustrated, will usually regain correct length and rotational alignment of the distal metatarsal segment.
The reduction may be held with pointed reduction forceps, applied perpendicular to the fracture planes.
Care should be taken to preserve soft-tissue attachments to the metatarsal, as stripping the intrinsic muscles away removes local blood supply and interferes with healing.
Intraoperative x-rays are helpful to confirm normal alignment of metatarsal length and head location.
Temporary K-wires may also be used for temporary reduction, with fixation to adjacent metatarsal(s), penetrating both cortices of the adjacent metatarsal(s). This will hold the fracture out to length.
4 Fixation topenlarge
Simple spiral or oblique fractures
A simple spiral fracture of a metatarsal if displaced and if it requires reduction is best secured with lag screw fixation.
A single lag screw is not enough and must be protected with a plate.
A transverse fracture requires compression-plate fixation.
Multifragmentary fractures are fixed with bridge plates as shown in the following steps.
The plate is applied to the dorsal surface of the metatarsal. This is generally straight, requiring only slight plate contouring.
Multifragmentary fractures in order to preserve their blood supply are bridged with a plate which is fixed to the proximal and distal fragment and will maintain their length and their proper axial alignment.
Clinical example: Plate fixation of fractures of the first to third metatarsal bones.